Strong Chirality Suppression in 1-D correlated Weyl Semimetal (TaSe4)2I

TL;DR

This study reveals that weak optical pumping causes a loss of chirality in the correlated Weyl semimetal (TaSe4)2I due to an optically driven phase transition, impacting its topological properties and potential for low-power optical control.

Contribution

We demonstrate that light-induced structural phase transitions suppress chirality in (TaSe4)2I, highlighting the importance of optical interactions in controlling correlated topological materials.

Findings

Chirality is lost above a threshold light intensity.

Raman spectra show a new peak indicating a phase transition.

System transitions into an achiral, non-Weyl phase at low powers.

Abstract

The interaction of light with correlated Weyl semimetals (WSMs) provides a unique platform for exploring non-equilibrium phases and fundamental properties such as chirality. Here, we investigate the structural chirality of (TaSe4)2I, a correlated WSM, under weak optical pumping using Circular Photogalvanic Effect (CPGE) measurements and Raman spectroscopy. Surprisingly, we find that there is a loss of chirality in (TaSe4)2I above a threshold light intensity. We suggest that the loss of chirality is due to an optically driven phase transition into an achiral structure distinct from the ground state. This structural transformation is supported by fluence-dependent Raman spectra, revealing a new peak at low pump fluences that disappears above the threshold fluence. The loss of chirality even at low optical powers suggests that the system quickly transitions into a non WSM phase, and also highlights the importance of considering light-induced structural interactions in understanding the behavior of correlated systems. These studies showcase that even low excitation powers can be used to control the properties of correlated topological systems, opening up new avenues for low power optical devices.